Tailgate / rear hatch panel removal and wiper motor testing / replacement, Volvo 850

Tailgate / rear hatch panel removal and wiper motor testing / replacement, Volvo 850

The rear window washer system worked fine. There is a secondary pump on the main washer fluid reservoir that supplies washer fluid through the floor of the car to the rear hatch. When I looked under the right side access panel in the rear floor area I can see the washer fluid tube running through the interior floor area. There is actually a filter or check valve about 1 foot from the rear hatch in the floor.

Flat Tip Screw Driver	Ohm Meter
12 mm socket	10 mm socket

Instructions:

Taking the rear panel off the hatch.

The light cover on the back hatch simply pulls off. With the hatch closed it pulls towards the front of the car.
Remove the trim from around the interior handle. Using the flat tip screw driver, pry under the edge of the trim and release the clips that secure the trim to the panel. It will click or pop and then you can pull it away from the door panel. If you look inside the door handle area you can see the seam that separates the trim from the panel.
Release the 4 clips that hold the panel on the bottom edge of the hatch. I used the flat tip screw driver to force them loose from the hatch. They simply push in when installing it so they pull out when removing it. The top will still be attached. Some cars have screws going through the panel into the hatch frame.
The top of the door panel can be pulled away from the hatch to release the 4 top clips but mine were to tight to pull loose. So with the bottom loose from the hatch, I was able to lift the panel causing the top clips to slide out of the hatch, they were still attached to the panel. My hatch panel had some kind of modification/repair done to keep the panel secure to the hatch and avoid rattling.
To remove the clips from the door panel, turn them 1/4 turn and they will come right out of the panel.
Repair or replace any broken clips and slide the upper 4 clips back into the hatch frame as explained in step 4.
To re-install the hatch panel, reverse the steps above.

If you need to do other repairs to the wiper motor, etc., continue below. If you need to fix or secure the panel to the rear hatch, use the instructions above to re-install the panel to the hatch.

Testing the wiper motor. My wiper motor was not wiping when the switch at the stalk was operated so I used the following steps to test the motor.

With the hatch panel removed, unplug the wire connector from the motor. It simply pulled loose.
The wire end of the connector has 3 wires. A ground (2 - orange), a intermit wipe power (3 - yellow/purple), and the constant wipe power (1 - green/orange).

To test the switch to make sure it is delivering power to the motor, turn the switch on "constant wipe", turn the ohm meter on to test for voltage (on my meter I had it turned around to the .50 V), place the ground wire on the #2 post and the power wire to #1 post. You should get a constant power reading (12 volts) to your meter. Then turn the switch on the "intermit setting", place the ground wire on the #2 post and the power wire to #3 post. You should get a pulsating reading to your meter from 0 volts to 12 volts. This will let you know that your switch is sending power to the motor.
NOTE: If you are getting power to the motor and it is not making your wiper work you have one of two problems. Either your motor is bad or you have a seized transmission/arm assembly.
Since I had good power, I assume my motor was bad. So I checked for continuity in the wiper motor.
To test continuity in the wiper motor I switched the ohm meter to check ohms. Then I placed the ground wire on pin #4 (on the motor) and the power lead (red) to pin #5 on the motor. Mine read 0 (zero) ohms. I then tested the other side of the motor, the intermittent side (pins #4 and #6) and still got 0 ohms. Then I did the same test on the spare motor I had from a V70 hatch and when I tested #4 and #5 pins it read almost 3k ohms.

That concluded my test of the rear hatch wiper motor. I determined that my rear wiper motor was bad and decided to replace the assembly. See instructions below.

To replace the rear wiper motor, it would be easiest to remove the assembly from the rear hatch.

With the rear hatch panel removed, lift the wiper bolt cover and remove the nut that holds the wiper to the rear hatch. I believe it is a 12 mm nut. The pull the wiper from the rear hatch.
On the inside of the hatch, remove the 3 bolts that hold the wiper assembly to the rear hatch. I believe they are 10 mm.
Once the bolts are removed you can pull the assembly away from the hatch. If you need to replace other parts on the assembly, it should be easy from there. If you have a cracked vinyl sleeve on the wiper base you can easily replace it now.
To reinstall the wiper motor/assembly simply reverse steps 13 through 11.